This PhD Thesis discusses the actual and potential impacts of Radical Right Parties (RRPs) on the economy and assesses these impacts – quantitatively and qualitatively – by considering the economic policy and performances of 27 European countries.We start discussing the different definitions of RRPs (Chapter 1) and their position on economic issues (Chapter 2 We derive an original taxonomy of RRPs’ positions on economic matters confirming the heterogeneity between RRPs. In Chapter 3, we critically review the literature on the political determinants of the economy and identify three conceptualisations of the ‘political’ in neo-classical economics: opportunistic, partisan, and institutional models. Chapter 4 tests our main hypotheses by using a dynamic panel data model. Results show no significant and robust evidence in support of an impact on authoritarian (e.g. security) and populist (e.g. deficits) indicators. We find evidence in support of a nativist impact, different in Eastern and Western European countries. In Eastern Europe, RRPs’ electoral scores, as well as their inclusion in a ruling coalition, are a significant predictor of increased imports and decreased exports. In Western Europe, RRPs’ strength and presence in a ruling coalition are a significant predictor of increasing gap in unemployment rates between native and foreign workforce.In order to understand the mechanisms behind our results, Chapter 5 proposes an original contribution to Amable and Palombarini (2005)’s neo-realist approach. We argue that economic policy is the result of the political regulation of social conflict and illustrate our framework with the case study of the Italian Lega Nord.